Its your choice I believe. When one of my friends got final decision for her pr back in 2023, her medical was to expire in 2 months. IRCC asked her if she would be able to travel in 2 months or if she wants to do another medical. She opted to do another medical because she was not ready. Now, she is settled in Canada with her family. I have forgoten how the letter was specifically worded. Remember, its a one time visa and if the person does not enter at the stated date, they have to re-apply for pr and start from scratch. So sometimes its better not to take the risk after months or years of waiting. Even with the COPR, unlike ECOPR given to applicants in Canada, overseas applicant do not officially become permanent residents until they arrive at a Canadian port of entry and their COPR is signed and dated by a CBSA officer.